Just so you know that you're not alone, I have had problems with my probe also but it doesn't seem to be the temperature of the unit. If the temperature of the meat is below a certain degree (and I'm not exactly sure what that temp is) the probe will not register. I thought I had bad electronics but, with Cookshack's help, I have replaced the controllers twice to no avail. What I do to get started is put the probe in the meat and connect it to the Amerique, set the cooker's temp, and then enter some high amount of time in (like 2 hours). Usually, after about 20-30 minutes, the meat is warmed up enough so that the probe then works. I just shut off the switch, turn it back on, and set the probe temp. All is perfect after that.
The more you use your Amerique, the more you are going to appreciate it. As far as I'm concerned, it makes all of its owners experts in the art of barbeque!!